RT Journal Article SR Electronic(1) A1 Marsh, D. G. A1 Crutchley, M. J.YR 1967 T1 Purification and Physico-Chemical Analysis of Fractions from the Culture Supernatant of Escherichia coli O78K80: Free Endotoxin and a Non-Toxic Fraction JF Microbiology, VO 47 IS 3 SP 405 OP 420 DO https://doi.org/10.1099/00221287-47-3-405 PB Microbiology Society, SN 1465-2080, AB SUMMARY The extracellular production of ‘free endotoxin’ from Escherichia coli sero-type O78K80 is discussed. Isolation of purified toxic and non-toxic fractions from crude extracellular material and the physico-chemical properties of these fractions are described. Purified free endotoxin possessed similar properties to endotoxins extracted from the bacteria by conventional procedures; a purified non-toxic extracellular fraction corresponded to the so-called ‘native hapten’. When dissolved in buffers containing sodium dodecylsulphate, the non-toxic fraction was not disaggregated, but the endotoxin produced sub-units of a smaller particle size than the non-toxic material. From these experiments it was concluded that the non-toxic material did not constitute simple sub-units of endotoxin., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-47-3-405